Compared to the stuff you see on amazon they are, but we have just had that conversation on the Oswu alarm system topic.
OP you get what you pay for, especially so with CCTV. In order to make something cheaper you have to produce it cheaper, like using plastic lenses that warp in the sun and cant be focused or reject chips that work but have been rejected due to dead pixels or similar.
I dont use Hik but they are what I would call the premium cheap end of the market, Hik are really good value for money from what I have seen of them. If you think Hik are expensive take a look at Mobotix, 6 times the price.
In answer to your question though any Onvif camera will work